Symptomatic Hyponatremia in Patients Undergoing Total Hip and Knee Arthroplasty

Clinically important hyponatremia is relatively uncommon. This disorder manifests with symptoms attributable to cerebral edema that include anorexia, nausea and vomiting, confusion, slurred speech, lethargy, weakness, agitation, headache, and seizures1. Symptoms are generally seen in an acute setting (developing over forty-eight hours or less) with serum sodium levels at or below 125 mEq/L (125 mmol/L) or in the chronic setting with levels at or below 110 mEq/L (110 mmol/L)1. If the disorder is left untreated or is corrected too rapidly, permanent neurologic sequelae can result. Surgical stress is recognized as a common cause of hyponatremia, most frequently in association with transplant, abdominal, cardiovascular, and orthopaedic trauma surgery2,3. This electrolyte disorder is more commonly present in elderly female patients, in those with a lower body weight, and in those taking certain medications, such as thiazide diuretics and selective serotonin reuptake inhibitors2.